Safety device for steam power plants



Oct. 28, 1930. M. EULE 1,779,967

SAFETY DEVICE FOR STEAM POWER PLANTS Filed Aug. 5, 192a F7 /8 4 .?6 35- 6 I o Q 4/; A9 94 i A Patented Oct. 28, 1930 UNITED STATES PATENT OFFICE MARTIN 'EULE, OF SPANDAU, GERMANY, ASSIGNOR '10 SIEMENS-SOHUCKERTWERKE 'GESELLSCHAFT MIT IBESGHRANKTER HAFTUNG, OF SIEMENSSTADT, NEAR BERLIN,

GERMANY, A CORPORATION OF GERMANY SAFETY DEVICE FOR STEAM POWER PLANTS Application filed August 5, 1926, Serial No.

My invention relates to a control device by which motions of an element confined in a chamber, in which apressure different from outside prevails, are transfered to the outside for making these motions available by outside means for controlling the forces or the conditions which cause the motion of this element in the chamber. By this novel arrangement, this motion can be transferred from the inside to the outside without the use -of stuffing boxes or similar expedients heretofore known in the art.

In particular my invention is applicable to steam generating plants.

My invention is particularly adapted as a control device for steam generatin plants for the purpose of remedying an a normal condition such as the generation of wet steam. In addition, with respect to steam generating plants, my novel device has the purpose of preventing wet steam from reaching the prime mover.

In operating steampower engines and more particularly steam turbines at high pressures, it is of the greatest importance that only steam practically free from liquid should enter the engines as otherwise serious breakdowns are liable to occur.

My invention is thus applicable in particular to a device which takes care that from a certain moisture content in the steam upwards the factors decisive for the satisfactory working of the plant are automatically controlled by the quantity of Water separated from the steam. As decisive factors come into account the operation of the furnace or the boiler feed water supply or the steam consumption or'a combination of them.

An embodiment of my invention is illustrated in the accompanying, drawings in v which in Figure'l.

' downwards.

127,421, and in Germany August 15, 1925.

tion is based is that the water separated from the steam operates a system of levers which either controls the steam generation or the steam consumption. A further feature of my invention is that the steam may simultaneously be dried in my improved device.

Referring to Figure 1, 1 is preferably a bend, or curved pipe located coaxially to an outer pipe 2. The steam from the boiler 34, only diagrammatically indicated, enters the device through the pipe 1 and escapes from the device though the pipe 2. When the steam passes from the pipe 1 into the wider pipe 2 the particles of liquid continue their progress in the previous direction owing to their greater momentum, while the specifically lighter steam more easily reverses its direction as indicated by the double arrow and passes along the annular space between the pipes 1 and 2 and through the bore 4 in the flange 3 and by way of supply pipe 22 to the steam engine or turbine 35, also indicated only diagrammatically. The pipe 2 is normally closed at its lower end 6 by. valve 33 or other suitable control means and forms a receptacle for the separated water 7. Into the pipe 2 is inserted in an airtight manner a "tube 8 which encloses a further tube 9. The tube 8 opens into the pipe 2 by a branch 10 while the tube 9 is closed toward the pipe 2. The tube 9 supports at its closed end a float 11. As long as there is no water in the receptacle 2, the tube 9 has to sustain the entire weight of the float 11 and, being made of 'quite thin material, is thus slightly bent Into the interior-of the tube 9 extends a double-armed lever 12 which is fulcrumed at 13 and abuts, withits end 14 against the inside of the tube 9. The other end 15 of this lever 12 carries a contact 16 which is adapted to co-operate with a stationary counter-contact 17. When the tube 9 is bent down by the weight of the float'the end 1 1 of the lever 12 is moved downwards and of the regulating devices to be controlled in dependence of the quantity of water separated from the steam. As has been stated matter of the present invention, my invention being applicable in all cases and to all kinds of steam plants wherever its presence may be advantageous.

Figure 1 further illustrates one of many possible ways which would suggest themselves to the skilled designer of the manner in which the float motions transferred from the inside of chamber 2 may exert their controlling influence upon a steam plant or other sources of power through which the conditions inside of chamber 2 are produced, such as the rising or falling of float 11. It is assumed in Figure 1 that by the closing or opening of the circuit 29, 30 a three way valve 18 may be actuated in which a valve body 19 is rotatable. This valve body has a transverse boring 20 and a radial boring 21 at right angles thereto, in the fashion of the well known three way cocks, so that communication may be established between the boiler and turbine 35 by way of the control device 2 and steam main 22 and service pipe 23 when the valve is in the position shown in Figure 1. On the other hand, when the valve arm 25 is turned downward, i. e. 90 from the position shown in Figure 1, connection with the turbine is shut off and direct connection is established through main 22 with condenser 36. In order to diagrammatically indicate how the current controlled by the contacts 16 and 17 of the control device may exert its controlling influence upon the valve as described, valve arm 25 is provided with a weight 31 which tends to throw it down into by-pass position to the condenser. Normally the end of the valve arm 25 is supported by a detent 26 fastened to an armature of a solenoid 27 which latter is energized by the current flowing through circuit 29, 30 when contacts 16, 17 are closed. A spring 28 tends to withdraw the armature from solenoid 27 so that it is held in the position shown in Figure 1 only so long as the circuit is closed at contacts 16, 17. As soon as it is opened, spring position shown. If, on the other hand, wet

steam should be generated through some cause in boiler 34, the moisture contained in the steam separates from the steam in the upper portion of chamber 2 by the means and in the manner described hereinbefore and, if the water thus accumulates in the receptacle 6 the buoyancy of the float 11 from a certain quantity of separated water upwards becomes so great that the tube 9 straightens. Since the lever 12 is provided with suitable means at its end, such as the enlarged heavy portion 15 which tends to force it downward, this lever moves downward when the tube 9 straightens and opens the contacts 16 and 17 i. e. the circuit is broken and the solenoid coil 27, being de-energized, lets go of its armature which is retracted by spring 28 and thus releases lever 25 which now drops down and switches the steam directly to condenser 36, so that the wet steam cannot injure the turbine.

It is desirable at the same time to use this control device not only for diverting the wet steam from the turbine butfor simultaneously remedying the abnormal conditions, by changing the steam generation such that it will produce dry steam, such for instance as by increasing the fuel supply.

While this feature does not form part of my invention, it is described merely for the purpose of showing to those skilled in the art, the different ways in which they may make use of my invention.

The steam generator 34, may have any of the well known fuel supply control means such as travelling'grates or other means indicated by the reference character 37.

These means may be driven by an electric motor 38, which receives its current from the supply line 39. The speed of the motor may be controlled in any suitable manner, for instance, by rheostat 40, 41; 40 indicating the resistance and 41 the rheostat arm. In shunt with the beginning of resistance 40 and rheostat arm 41 is arranged a short circuit 42, 43 which is controlled'by a contact device 44. One element of this contact device is connected with the armature 46 of a solenoid 45 which latter is en ergized from the same source 32 which furnishes current into circuit 29, 30 which energizes solenoid 27 as previously described. A spring 47 tends to draw the armature 46 upward and to thus hold the contact device closed, whereas when solenoid 45 is energized, it puts spring 47 under tension and holds the contact of the device 44 in open position. This occurs so long as contacts 16 and 17 of the control device are closed and so long as the plant is in normal condition. In this condition, rheostat arm 41 may be in any position required to run motor 38 at its proper speed. If now the abnormal steam condition referred to hereinbefore develops and suflicient water accumulates in the control device to open contacts 16, 17, the

energizing circuit through solenoid 45 is opened and spring 47, coming into action closes contact device 44, which in turn short circuits the rheostat portions 40, so that now the motor speed will be increased and thereby speed up the operation of fuel supply device 37.

It is obvious that the device illustrated by way of example may not only be employed in the described manner as a safety device in dependence on the quantity of liquid separated from the steam but also in all cases where occurrences in airtight sealed chambers should control apparatus without movable parts being passed through the chamber by means of stufling boxes or the like. The main advantage of my improved device resides in the feature that all the parts standing under pressure may be sealed absolutely airtight since the motion is derived at places which are not in communication with the interior of the chamber.

The action upon the control members need,

of course, not take place in an electrical manner but in any other suitable manner, for instance in a purely mechanical one. In the latter case the further advantage is obtained that electrical currents cannot come in contact with the steam and decompose it so that the danger of the development of explosive gases is entirely avoided. A manner in which this mechanical function may be arranged is shown in Figure 2. In this figure, 12 represents the lever of the control device shown in Figure 1. Its outer end is provided with a weight 52 and this end rests on the short arm of a bell crank 50, the vertical arm of which serves as a support for the valve arm 25 of three way valve 18 described as to its function with respect to Figure 1. So long as float 11 exerts more or less its own weight upon flexible v,tube 9, weight 52 is substantially supported, and does not exert any pressure upon the' short arm of bell.

crank 50, which latter then supports arm 25 in the horizontal position,which corresponds with the'hori zon'tal position of arm 25 and the valve position shown in Figure 1. If,

however, by the accumulating water in the bottom of the control device, float 11 is gradually raised and bends tube 9 upwards, weight 52 gradually exerts a pressure upon the short arm of bell crank 50 and thereby withdraws the supporting long arm of the bell crank from the end of the lever 25 so that the latter will drop down in the manner described hereinbefore. J

The lower portion 6 of the control device in which the condensed water accumulates may be drained by means of a draining valve 33 every time when the control device has responded. Since thiscontrol device comes into action only off and on, when abnormal conditions prevail in the plant and since in practice the condition arises infrequently,

reverse direction, out of said chamber to separate the water contained in the steam, a float in'said chamber, rising and falling with thewater level therein, an elastic hollow body protruding into said chamber and :being closed at its inner end, a connection between said float and said body enabling the. float by its rise and fallto deform said body, and means for transferring the deformations of said bodv to the outside topermit the 'control thcrethrbugh of the plant operation in ac-- corclance with the moisture contents of the steam.

2. A safety control device for steam generating plants or the like comprising a chamber, means for conducting steam into and, in'

reverse direction, out of said chamber to separate the water contained in the steam,'a float in said chamber, rising and falling with the water level therein, an elastic tube protruding into said chamber and being closed at .its inner end, a connection between said float and the inner end of said tube enabling the float y by its rise and fall to deform said tube, a

double armed lever pivotally mounted adja-- cent to the outer end of said tube and extending with one end to the inner end of said tube and means for holding the end of said inner arm in contact with the inner end of said tube tofollow the deformations of the latter for transferring the float motions through 'said tube deformations to the outer arm of said lever, and means, governed by the movement of said outer arm, adapted to control the operation of said plant.

A safety control device for steam generating plants or the like, comprising a cham-- ber containing in its upper end a steam admission duct and a steam discharge duct both arranged to force the steam to reverse its direction when passing in the chamber from one duct to the other for separating the moisture contained in the steam, a float in the lower portion of said chamber, rising and falling with the water level therein, an elastic hollow body protruding into said chamber and being closed at its inner end, a conncction between said float and said body enabling the float by its rise and fall to deform said tube, a double armed lever ivotally mounted adjacent to the outer end of said tube and extending with one end to the inner end of said tube and means for holding said inwardly extending arm'end in contact with the inner end of said tube to follow the deformations of the latter for transferring the float motions through said tube deformations to the outer arm of said lever, and means, governed by the movement of said outer arm, adapted to control the operation of said plant.

4. A safety control device for steam generating plants or the like, comprising a chamber containing in its upper end a steam admission duct and a steam discharge duct both arranged concentrically one within the other to force the steam to reverse its direction when passing in the chamber from one duct to the other for separating the moisture contained in the steam, a float in the lower portion of said chamber, rising and falling with the water level therein, an elastic hollow body protruding into said chamber and being closed at its inner end, a connection between said float and said body enabling the float by its rise and fall to deform said tube, a double armed lever pivotally mounted adjacent to the outerend of said tube and extending with one end to the inner end of said tube, and means for holding said inwardly extending arm end in contact with the inner end of said tube to follow the deformations of the latter, for transferring the float motions through said tube deformations to the. outer arm of said lever and means, governed by the movement of said outer arm, and adapted to control the operation of said plant.

In testimony whereof I aflix my signature.

. MARTIN EULE. 

